f t / I t KHOA HQC - CONG NGHE
/ I
GIAI PHAP EPS VA KHA NANG IMG DONG TRONG XAY D U N G CONG TRINH TREN OAT YEIJ TAI VICT NAM
TRUONG QUOC BAO Hoc vien Ky thuat Quan sU
PHAM HOANG KIEN Dai hoc Giao thdng vdn tdi
V U A N H T U A N Hpc wen Ky thuat Qudn sU
T o m tat: Xay dyng cong trinh trdn n i n d i t y l u da va dang la nhdng thach thdc doi vdi eac ky s y trong viec tim ra cac giai phap x d ly n i n , n h i m gia tang sde ehju tai, hay cai thien ehi tieu ea ly eua d i t n i n , d l dam bao d i i u kien khai thae binh t h y d n g eua edng trinh. Hien nay, xu h y d n g s y dyng nhdng loai vat Ngu nhe lam giam tai trpng tac dung, giam kha nang b i l n dgng pha hogi n i n , cung ngay cang t r d ngn pho b i l n trong xay d y n g eong trinh tren nen dat y l u . D y a vao y u d i i m la mgt vat lieu nhe nhyng cd c y d n g do eao, EPS Geofoam d y p e dng dung trong cae eong trinh giao thdng ( D y d n g dau cau, d y d n g dap cao, on djnh mai d i e , d y d n g trdn nen dat ylu...) d mpt s l q u i c gia trgn t h i gidi. Bai bao trinh bay nghien cdu tong quan v l vat lieu EPS va d l xuat mpt s l kha nang dng dung vgt lieu EPS vao xay d y n g cdng trinh tai Viet Nam.
TCF k h o a : EPS Geofoam, n i n d i t yeu, eong trinh trgn n i n d i t yeu.
A b s t r a c t : Construction on the soft ground has been a great challenge for engineers to find out solutions to improve the soil for increasing the bearing capacity or improve the mechanical properties of the soil, to ensure the normal operating conditions of the works.
Nowadays, the tendency to use lightweight materials to reduce the toad on the ground is more and more popular in building construction on soft ground. As a lightweight and high-strength material, EPS Geofoam is applied in traffic works (Bridge approach embankment, high embankment,
slope stabilization, roads on the soft ground...) in several countries all over the world. This paper presents an overview of the EPS material and suggests some of the possibilities for the application of EPS materials into construction works in Vietnam.
Keywords: EPS Geofoam, soft ground, construction on the soft ground.
LDATVANDI
Trong xay dyng cdng trinh giao thdng ndi ehung, viec xay mdi d y d n g cao t i e , d y d n g d i n dau cau, nang c i p eai tgo eac t u y i n d y d n g cu... ygu cau dam bao do b i n va s y on djnh lau dai cua nen d y d n g , eo y nghTa q u y i t djnh den hieu qua khai thac eCia t u y i n d y d n g . Vdi dae diem n y d e ta, cac do thj va trung tam kinh t l ldn nam d khu vye dong bang sdng H i n g va song Cdu Long. Day la eac khu vye ed d i i u kign t y nhien thuan Ipi cho giao thyang nhyng x e t v e khia canh xay dyng thi bat Ipi vi eac ldp n i n la t r i m tieh sdng b i l n cd cau tao phde tap, trong dd, cd nhdng Idp d i t y l u phan b l tren dien rgng va b l day Idp ed t h i Ign tdi 40 - 50m. Vi vay, ehi phi xay dyng edng trinh ed t h i tang thgm 10 - 20%.
Doi vdi n i n d i t y l u , n h i l u p h y a n g phap gia c l n i n da d y p e nghign cdu va dya vao dng dyng nhy: Giai phap s d dyng b i e t h I m k i t hap gia tai tryde hoae hut chan khdng, s y dung be phan ap, epc cat, epc xl mang d i t , cgc gia c y d n g , vai dja ky thuat...Tuy nhien, vige ap dung eac giai phap truyen thong
nay x d ly n i n d i t y l u trong mpt s l t r y d n g hpp v i n ehya dgt ygu e i u , dan d i n s y eo eong trinh nhy hign t y p n g t r y p t n i n d i p d y d n g dSn Ign eau Hoang Long - Thanh Ho^, lun tuyen d y d n g N g u y i n Hdu Canh - TP Hd C h i Minh... Hinh 1 \d mpt vi du v l h y hdng n i n dydng phan t i i p giap gida cau va dydng dan d i u eau do nguyen nhan liin Igch.
Hinh 1. Hw hdng nen dap dwdng din len ciu do lun lech
Vi vay, viec lya chgn giai phap thi cdng thich hpp eho moi edng trinh, bao dam eac yeu to lien quan d i n dat n i n nhy doi t y p n g x d I;/, vat lieu va trang t h i l t bj thi cdng, phyang tign x d ly, gia thanh, anh h y d n g ddi vdi khu v y e lan c^n, mdi trydng.,. la mgt ygu cau cap bach va cd tinh thye t i l n cao trong giai doan hien nay.
So 4 nam 2020 I
KHOA HOC - CONG NGHE MM MS
I. Gldl THl£U GIAI PHAP EPS ITA KHA NANG UMG DUNG TAI VIETNAM
2.1. Giai p h a p EPS ( E x p a n d e d Polystyrene)
^ d i dgc t r y n g cua vat lieu nhe co khoi l y p n g the tich vao khoang 1 - 70% so vdi d i t hoae da. Do do, ed nhieu loai vgt lieu nhe khac nhau d y p e s y dung, bao gom vat lieu cd kha nang chiu nen nhy: X l p , be tong bpt va vdt lieu dang hat xl Id, tro bui, g i m nd... Hien nay, vat lieu d y p e s y dung pho bien han ca la x l p polystyrene n d , vdi y u diem de gia cong, bao quan va cd khoi l y p n g the tich t h i p . Trong do, vgt lieu nhe EPS (Expanded Polystyrene) ed k h l i l y p n g the tieh chi b i n g 1 % ~ 2 % so vdi dat, da hoae bg tong, d i n g thdi ed the ehju d y p e d n g s u i t nen ldn. Vi vgy, viee s y dung EPS lam vgt lieu d i p eho cdng trinh cd tai trpng nhe khdng can x d ly nen b i n g cac p h y a n g phap n h y : Gia tai t r y d e , try d i t vol, xi mang... D i i u nay lam giam gia thanh va thdi gian thi edng. Hinh 2 t h i hign nhdng dae d i i m chung, tieu b i l u eua giai phap EPS.
Giai phap EPS d y p e dng dyng d i u tign vao nam 1972 tai Na Uy [2], eae k h l i Geofoam d y p e lam bang Expanded Polystyrene (EPS) d y g c san x u i t eho muc dich lam vat lieu d i p , khoi l y p n g nhe (xem Hinh 3), lam giam ap l y c dat va mgt sd d n g dyng khae trong xay dyng, giai phap da d y p e ap dung t/a phat trien d n h i l u quoe gia trgn :hg gidi.
\/at lieu EPS rat nhe va ed the J y p e san x u i t d n h i l u hinh dgng / d i trpng l y p n g rieng r i t be, g = D,12 - 0.35 kN/mMkhoang 1/100
;o vdi d i t ) . Cac k h l i Geofoam dng l u n g eho edng trinh xay d y n g va :ong trinh giao thdng t h y d n g cd cieh t h y d e 0.5^1.0x2.5 - 3.0 m, choi l y p n g 25 - 30 kg. Theo cong )o cua Aab0e eung cgng s y [1] va
^adade A. H cung cdng s y [9, 10],
8 6 4 nam 2020
c y d n g dp vat lieu EPS thay doi t u y i n tinh theo trgng l y p n g rigng cua vat lieu. Bang 1 trinh bay cae dac tinh c a hpc cua EPS [9]. Hinh 4 trinh bay d y d n g cong quan hg dng s u i t - b i l n dang eua EPS t d k i t qua nen ba true dng vdi eae trpng l y p n g rigng 0.15; 0.20; 0.22 va 0.30 kN/m^ [10], Nhan thay khi
b i l n dgng dgc true nho han 2%
thi quan he dng s u i t - b i l n dgng la t u y i n tinh. Sau do, dng s u i t cd xu h y d n g tang cham va g i d on djnh d gia trj eye dgi du b i l n dang t i i p tuc tang. Dp lech dng s u i t thay doi khdng dang ke khi thay doi eae e l p ap lye hdng 50; 100 va 150 kPa.
^IfCi^n
C u ^ n g d o nen 2 0 - 2 0 0 kN/m2
^ T^riap
B i e n d a n g h d n g rat it
c
E P SJ H > 1/100 t y t r o n g dat
T h i c d n g Cd the lap va van chuyen bang sdc ngydi
Kinhtg Khdng ^ £ n
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6 n d j n h c a o n g a y ca d p n g d a t
Rut ngan thdi gian thi cong, khong anh hudng xung quanh, duy tu bao tri d l dang Hinh 2. Bac diem giai phdp EPS
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Hinh 3. Thi cong EPS ehdng lun cho nen dwdng tai Oslo, Na Uy, 1972
Trpng lugng rieng
{mim')
0.15 0,20 0,22 0.30
Bang 1
Cu'dng do chiu nen (kPa) 61.95 91.39 110.53 146.80
. Cac dac tinh cahoc Cuang 36
chju keo (kPa) 154.69 216 40 244.64 407.78
Ci^ong 36 chiu u6n (kPa) 149.9 211.3 240.6 277.0
ouaEPS[9]
Cuaug dp chju cat
(kPa) 83.65 94.37 121.57 139.27
IVIo dun tiep tuyin ban d§u
(kPa) 2480 76 4070.65 5608.16 7560.28
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^ I t l t KHOA HOC - CONG t^GHE
SO
| 7 0 i 50
Densitv = 0 15kN/iii'
/ " " " ' ^ ^
S i , n Confining Pressure = 50 kPfl
* 20 Q AConfimngPiesaire^ lOOkPa 10 ' O ConTining Pressure = ISO kPa
S 60 2 sn
Dengly = 0,2QkNW
cr • Confining Pressure
^ ^ Conjining Piesure , O Confining Pressure
SOkPa 100 kfa 150 kPa
• Confining Pressure = SO kPa AConfuung Pressure^ 100 kPa oConfuilnglPressuFE = ISOkPa
* 140 1 120 2 «n
\ 60
° 40 DensHy=OJOkNW
ji^ssnraiiBi!RB||;og|[
i
^ Q Confining Pressure - 50 IcPa
?• AConfiningPressure-lOOkPa P O Confining Pressure = 150 kPa
I
Hinh 4. Quan he irng suat-biin dang ci^a EPS tir kit qua nen ba true irng vai cac trgng Iwgng rieng
khae nhau [10]
Vdi dgc tinh ehong t h I m n y d e , h l u n h y khdng h i p thu n y d e , mat dd va tinh nang khdng doi bdi n y d e , b i l n dgng hdng it khi chat tai, vat lieu nhe, thuan Ipi cho thi edng, khdng can dam nen va quan ly dam nen, ap dyng trong dieu kidn khdng the s d dung may moc c a ldn, thdi gian thi cdng n g l n .
Hien nay, giai phap EPS da d y p e s d dung d n h i l u q u i c gia tren t h i gidi dgc biet eae quoc gia Chdu Au nhy: Cdng hda Sec, fide, Hy Lgp, Ha Lan, Na Uy, Ba Lan, Serbia, Thuy O i l n , Anh ...ap dung thanh cdng vao ITnh v y c xay d y n g cdng trinh giao thdng va xay d y n g dan dung [4, 5, 7, 8 , 1 1 , 1 2 ] , Cf Chau A, nhieu q u i e gia cung da dng dung
thanh cong giai phap EPS trong x^y dyng nhy Nhat Ban, Trung Quoc, Malaysia, Thai Lan, Philippines, Han Quoe va Dai Loan, An Bp....
[3, 6, 13, 14]. Hinh 5 la mot vi dg v l vige s d dung EPS de thi cdng n i n d y d n g trgn dat y l u tgi Ha Lan.
Hinh 6 la hinh anh vige s d dung EPS d l thi edng nen d y d n g tgi Sapporo, Nhat Ban.
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Hinh 5. ifng dyng EPS cho nin dat yiu tai Ha Lan
Hinh 6. Wng dung EPS cho nen dat yeu tai Sapporo, Nh$t Ban
Hinh 7 t h i hien so lieu viee s d dung EPS trong xay d y n g tgi Nhat Ban tinh t d nam 1986 d i n h i t nam 2017. Nhan thay k h l i l y p n g luy k l EPS dygc s d dyng tai Nhat Ban tang t u y i n tinh theo thdi gian, chdng to s y hieu q u i eua EPS trong xay dyng.
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Hinh 7. Thirc te ung dung giai phip EPS tai Nhat Ban (Tham khao s6 lieu thdng ke cua OKLSLN LIVIC CO, LTD)
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So 4 nam 2020 IKHOA HOC - CONG NGHf MM Mi
Giai phap EPS cho xay d y n g eong trinh trgn d i t y l u cd the d y p e khai quat qua cae b y d e thi edng n h y sau:
- Cong tac ehuan bj mat bang thi eong (Hinh 8a);
- L i p dgt thiet bj va khoi EPS (Hinh 8b);
- L i p dgt cot thep va d l bg tong (Hinh 8e);
- Hoan thien (Hinh 8d).
Hinh 8d. Hodn thien Hinh 8. Thi cong EPS tren nin dit yiu
2.2. Kha nang u-ng dung tgi Vl?t Nam
V d i dac tinh cua vat ligu nhe EPS ke tren, nhan t h i y kha nang dng dung giai phap EPS trong xay d y n g eong trinh trgn n i n dat y l u
tai Vigt Nam la kha thi, Viee s d dung EPS thay the eho vat ligu dap thong t h y d n g se giup giam tai trgng cdng trinh, han c h i d y p e s y gia tang dng s u i t hdu hieu trong d i t , t d do giam, tham ehi ed t h i logi bo d y a c dp ldn eua n i n .
Khi dng s u i t hdu hieu tac dung Ign day khoi mdng ldn han dng s u i t hdu hieu do edt d i t tao ra, thi khoi mdng se x u i t hien hien t y p n g lun.
N l u ta thay t h i k h l i d i t trong Idng mdng bang vat lieu nhe thi EPS gay ngn dng s u i t hdu hieu t y a n g d i i nhd. N l u t h i l t k l chieu sau mdng mot each thi'ch hap thi dng s u i t tac dung ldn day k h l i mdng x i p XI bang dng suat hdu hieu do cot d i t gay ra. Trong t r y d n g hap nay se khong xay ra hign t y p n g lun hoae dp lun r i t nhd. N h y vay, vdi eae edng trinh s d dung p h y a n g phap mdng noi hoae eong trinh bj h y hai do k h l i dat trong Idng gay lun ta cd t h i thay t h i k h l i d i t nay bang vat lieu EPS n h i m lam giam tai tac dung len day mdng, qua do, cd the lam giam hoae ddng han hien t y p n g lun eua edng trinh.
Trong thdi gian thi cong n i n d y d n g bang d i t dap, tai trpng tae dung Ign n i n dat tang d i n ngn do lun tang nhanh, sau khi thi eong xong tai trgng khong doi lue nay chi cdn dp lun t d b i l n . Tuy theo c l u true dat n i n ma do lun trong thdi gian lun t d b i l n la ldn hay nho, t i l n hanh d d bd toan bg khoi dat da thi cdng, lue nay dng s u i t bang 0. N l u ta thay t h i vat lieu d i p la EPS, t i i trpng eua n i n d y d n g tae dung Ign n i n dat chi do Idp cau tao mat d y d n g gay ra va tai trpng nay nhd han han tai trpng do k h l i d i t gay ra, dp lun sinh ra nho han so vdi dung vat ligu d i t d i p . Sau day la mdt s l de xuat dng dung vat ligu EPS trong xay d y n g cdng trinh tai Viet Nam (Hinh 9):
P a p nen dat yeu
Hmh 9a Thi eong nen dap tren dat yeu Hmh 9b. Thi cong nen dip
sau mo eiu
I So 4 nam 2020
mm
MMMMM KHOA HOC - CONG NGHE
• - • ^ ^ ^ . ^ ^ ^ i ^ j L , . , ^ ,
Hinh 9e. Thi cdng nin dip mai doe Hinh 9e. Vat lieu dip tren
cdng tnnh ngim Hinh 9. Mpt s o de x u i t d n g dung EPS trong xay d y n g c o n g
trinh tai Viet Nam De cd the d y a giai phap EPS vao dng dung trong xay dyng cdng trinh Vigt Nam thi can phai t i l n hanh eae nghien edu thd nghiem d l kiem ehdng s y phCi hap cua giai phap doi vdi d i i u kign thye t l tai Viet Nam, Hign nay, cdng ty Okasan Livic (Nhat Ban) dang t i l n hanh thi cdng thd nghiem mpt nen d y d n g d i p s d dung vat lieu EPS trgn nen dat y l u tai tinh Ba Rja- Vung Tau (Hinh 10). K i t qua thd nghigm se d y a c cdng bo trong thai gian tdi.
Tuy nhign, vdi d i i u kign dja chit eCia Vigt Nam vige s d dyng vgt ligu nhe la xu h y d n g cd nhieu triin vpng, dac bigt, khi xay dyng dydng giao thdng trgn n i n d i t yeu va xij ly lun cdng trinh xay d y n g . De giai phap EPS CO t h i ap dung tai Vigt Nam can phai t i i p tuc nghien edu, thi nghigm vdi d i i u kien dja chit, dieu kien t y nhign eung nhy bign soan cac tieu e h u i n t h i l t k l , thi cdng phu hap. •
Hinh 10. Thir nghiem nen 6 bing EPS tai Ba Rja - Vung Tau,
Viet Nam
3.KIENHGHIVAKETLUAH Giai phap EPS d y p e s d dung pho b i l n d n h i l u quoc gia han 40 nam, vdi y u diem ciJa EPS la loai vat lieu nhe, ed e h i t lypng ddng n h i t , ed cae dae tinh ea hpc t i t , phii hap cho xay dyng edng trinh trgn nen d i t y l u . Vi vgy, EPS t h y d n g d y a c s d dyng vdi mue dich lam giam dp lun eua cong trinh va rut ngan thdi gian thi edng.
TAI UEU THAM KHAO
1. Aaboe R., Barlelt S.F., Duskov M., Frydenlund TE., et al. (2018). Geofoam block in civil engineering applications. 5th Intemational Conference on Geofoam Blocks in Constniction Applications, pp. 3-38,
2. Alfheim S., Flaate K., Refsdal G., et al. (2011). The first EPS geoblock road- embankment-1972. 4th International Conference on Geofoam Blocks in Construction Applications. Lillestrom, Norway
3. Aunaas, K. (2011). Recent impressions from EPS projects in Japan. 4th Intemational Conference on EPS Geofoam Blocks in Constwction Applications, Lillestram, Norway.
4. Beinbrech G., Hillmann R. (1997). EPS in road construction-cun-ent situation in Gemiany Geotext Geomembrane 15(1-3), pp. 39-57.
5. Herle V. (2011). Design and monitoring of EPS embankment on Dl near Ivanovice in the Czech Republic. 4th International Conference on Geofoam Blocks in Construction Applications, Lillestr0m, Nora/ay
6. Kim, H., Joo, T, Yoo, K., Han, T, Kim, T, and Jung, J. (2003). Case studies of EPS failure and quality control by site monitoring. Proceeding of the Korean Geotechnical Society 2003 National Conference, Daejon, Korea, March 21, Korean Geotechnical Socie^, pp. 401-408, In Korean.
7. Milan D., Martin D.U. and Michael F. (2018). Dutch A75 highway widening using EPS embankment with a vertical side. 5th Intemational Conference on Geofoam Blocks in Construction Applications, pp. B^-Q7.
8. O'Brian AS (2001) Design and construction of the UK's first polystyrene embankment for railway use. 3rd Intemational Conference on Geofoam Blocks in Construction Applications, Salt Lake City, USA.
9. Padade A. H. and Mandal J. N. (2012). Feasibility studies on expanded polystyrene (EPS) geofoam. Intemational Conference on Ground Improvement and Ground Technique, lGCl-12, Oct 30 - Nov 2, 2012, University of Wollongong, Wollongong, Australia.
10. Padade A. H. and Mandal J. N. (2012). Behavior of expanded polystyrene (EPS) geofoam under triaxial loading conditions. Electronic Journal of Geotechnical Engineering, 17, pp. 2543-2553.
11. Papacharalampous G., Sotiropoulos E, (2011), First time application of expanded polystyrene In highway projects In Greece. 4th intemational conference on geofoam blocks in constmction applications, Llllestrem, Nonway 12. Spasojevlc S., Mitrovic R, Vujanic V, et al (2011), The application of EPS in geotechnical practice: a case study from Serbia. 4th intemational conference on geofoam blocks in constmction applications, Lillestr0m, Nonway.
13. Tsukamoto H. (1996). Slope stabilization by the EPS me&iod and its applications, Intemational symposium on EPS constmction method (EPS Tokyo '96'), EPS construction method development organization, Tokyo, Japan, pp. 362-380.
14. Youwai S., Kongkitkul W., Sripobink J. et al (2011). Application of EPS for remedial work of bridge bearing unit on Bangkok Soft Clay: A case study. 4th intemational conference on geofoam blocks in constmction applications, Lillestrom, Nonway